I like my D-20. It sounds very similar to the D-50. I don't use the sequencer because computer sequencers are much better. The synth is the same as the Roland D-10 so the patches are 100% compatible. The D-110 module is almost the same but I think that there are some differences.

dirk sontowski ,am richtsberg 6, 35039 marburg, germany : having an 8-jears old "vintage" synthesizer it is still fun to work with .the analog qualities of the d20 are probably under-estimated, but if you put some time into sound programming the results are very convincing. there are 2 points that over-shadow the result: 1. the built-in sequenzer is not that usefull especially a copy function would be very nice ! 2. the keyboard-quality is rather poor. though i bought it as secound hand,and the first owner totured it obviously very much, the quality of roland keyboards is not the best. yamaha does it better! never the less i would buy the d20 again cause typical trance-sounds are possible to get with it. it does'nt have to be one of these overprized, difficult to get , not midified and unreliable dinos! Synthsite Comment: It's very simillar to the D110 module but with a sequencer. Good lo budget synth but you will need to work at the sounds a bit. There were a lot of sounds for it floating around at the time of release because of the simillarity to the d10,d110 etc I think Roland shifted a lot of these units. The sysex implementation is cool, it's possible to dump the edit buffer so you never had to store the sounds in memory.

Comments About the Sounds:
The presets aren't good but you can make some cool sounds yourself. The synth is fully programmable. You can combine samples and saw/square waves if you want. The filter is pretty cool. There's one great disadvantage: You can't filter samples!

(Thanks to Johan Nilsson for this info.)
and Per Kr. Johansen for the pic